TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3348 SUBJECT: GRB 050504: A long GRB detected with INTEGRAL DATE: 05/05/04 09:13:04 GMT FROM: Sandro Mereghetti at IASF/CNR S. Mereghetti, D. Gotz (IASF, Milano), N. Mowlavi, S. Shaw, M. Beck, M. Turler (ISDC, Versoix) and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: A long GRB has been detected by IBAS in IBIS/ISGRI data at 08:00:52.5 UT on May 4. Its coordinates (J2000) are: RA: 200.9986 [degrees] DEC: +40.6959 [degrees] with an uncertainty of 1.5 arcmin (90% c.l. radius). Note that this burst is located at high galactic latitude (b=+75 deg) and not affected by Galactic absorption. It is therefore a good target for optical follow-up searches. Analysis of the IBIS/ISGRI data yields a peak flux of 0.5 photons (6E-8 ergs)/cmsq/s (1 s integration time) and a fluence of 14.4 photons (1.5E-6 ergs)/cmsq (80 s integration time). Both values refer to the 20-200 keV energy range. The burst lasted about 80 s and had a FRED profile. A plot of the light curve can be found at: http://ibas.mi.iasf.cnr.it/IBAS_Results.html This message can be cited.